Torque controlled outboard motor propeller



SePt- 18, 1962 F. M. MGNEILI.

TORQUE CONTROLLED OUTBOARD MOTOR PROPELLER Filed March 19, 1958 Il@ S 3,054,457 TORQUE CONTROLLED OUTBO MOTOR PROPELLER This invention relates to a propeller, and more particularly to a propeller for an outboard motor.

The object of the invention is to provide a torque controlled reversible pitch outboard motor propeller which will shift from reverse to forward pitch and vice versa as the torque is increased or reduced .so that the propeller is responsive to throttle setting and wherein the propeller is easily controlled.

Another object of the invention is to provide a torque controlled reversible pitch outboard motor propeller which is easy to install, and which is readily controlled and wherein the propeller is extremely durable and eicient to use.

A further object of the invention is to provide a torque controlled reversible pitch outboard motor propeller which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

FIGURE l is an elevational view illustrating the torque controlled reversible pitch outboard motor propeller of the present invention.

FIGURE 2 is a sectional View taken through the propeller.

FIGURE 3 is a transverse section of FIGURE 2 on the line 3-3 thereof.

FIGURE 4 is an elevational View partly broken away of the front body member of the propeller.

FIGURE 5 is an elevational view partly broken away of one of the intermediate body members.

FIGURE 6 is an elevational view partly broken away of the rear body member.

FIGURE 7 is a perspective View showing the various parts of the propeller disassembled.

FIGURE 8 is a perspective View of the coil spring employed in one form of the invention, and

FIGURE 9 is a perspective View of the cylindrical rubber bushing that may be substituted for the coil spring of FIGURE 8.

Referring in detail to the drawings, and more particularly to FIGURES 1 through 8 of the drawings, the numeral 10 indicates the propeller of the present invention, and it will be seen that the propeller 10 includes a plurality of similar leaves or body members which are indicated by the numeral 11, and these members 11 include a front body member 12 and a rear body member 13 as well as similar intermediate body members 14.

As shown in the drawings, all of the members 12, 13 and 14 have the same construction, and each is provided with a central intermediate circular bore or opening 15, for a purpose to be later described. Each member is further provided with notches 16 which define therebetween offset tabs 17. The numeral 18 indicates a cylindrical hub which extends through the bores 15, and the hub 1S has one end integral with the front body member 12, as shown in FIG. 3, the intermediate body members 14 and the rear body member 13 being free to rotate on the hub 18.

As shown in the drawings, there is further provided a drive shaft 19 which has a threaded end portion 20, and the numeral 21 indicates a cone shaped spinner, and the spinner 21 is provided with a threaded recess or socket 3,054,457, Patented Sept. 18, 1962 for receiving the threaded portion 20 of the shaft 19. The numeral 22 indicates a set screw which extends through the spinner 21 and engages an end of the shaft 19. There is further provided a shear pin 23 which extends through the hub 18 and through the shaft 19 for connecting the hub and shaft together. The numeral 24 indicates a resilient means which in FIGURES 2, 3 and 8 is shown to comprise a coil spring, and the coil spring 24 is circumposed or mounted on the hub 18. Instead of using the coil Spring 24, a rubber insert or resilient cylindrical bushing 25 as shown in FIGURE 9 may be used, and the resilient bushing 25 is provided with spiral cuts or recesses 26. Y

From the foregoing, it is apparent that there has been provided a torque controlled reversible pitch outboard motor propeller wherein the present invention will make available to owners of non-reversible outboard motors a series of inexpensive and easily installed reversible pitch propellers which are caused to shift from forward to reverse pitch and vice versa, by the increase and reduction of torque, and is thereby responsive to throttle setting and easily controlled.

As shown in the drawings, the propeller includes a plurality of similar pieces of sheet brass or other suitable corrosion resistant material which are indicated Iby the numeral 11, and these members may be referred to as propeller leaves or body members. The front and rear propeller leaves or body members 12 and 13 are connected at opposite ends of a coil spring 24, FIGURE 8, or rubber sleeve 25, FIGURE 9. The intermediate members 14 slip over the coil spring 24 or rubber sleeve 25 but are not connected to it. All body members and the coil spring or sleeve slip over a cylindrical hub 18 and Vonly the front propeller member 12 is connected to this hub. All other body members 13 and 14 and the coil spring or rubber sleeve are free to turn on the hub.

All of the body members are bored or provided with the openings 15 for receiving the coil spring or rubber sleeve and hub. Arranged adjacent the circumference of the bores 15 at one or more places, but at the same places on each body member, two notches 16 are cut, and the tabs 17 remaining between these notches are bent to the rear far enough to engage the notch in the succeeding rear propeller member. The result of this is to limit the amount of movement of each body member in relationship to its neighbor, and at each extreme of pitch (forward and reverse) to align the body members. The function of the tabs 17 and notches 16 will be described more fully later in this specification.

The propeller assembly further includes the shear pin 23, and the cone shaped spinner 21 which has the set screw 22 extending therethrough so that the body members are retained on the hub and wherein the spinner 21 will provide a finished streamlined appearance to the completed propeller assembly when screwed onto the threaded end 20 of the shaft 19.

In use or operation, torque is transmitted through the hub 18 directly to the forward member 12, and at low rotational speeds the coil spring 24 or rubber sleeve 25, which has purposely been installed under tension, rfor this purpose, holds the rear propeller leaf or member 13 in an an gularly advanced position from the forward propeller member 12 in reverse pitch position as shown in FIG- URE l. The tabs and aligning notches align the intermediate members 14 and limit the extent of this advance.

At a slightly increased rotational speed, water resistance to propeller torque begins to overcome the restraining effect of the coil spring or rubber sleeve, and pushes the intermediate and rear propeller members far enough out of line to eliminate reverse pitch and to align the members to achieve the effect of a neutral gear position on motors which Vare so equipped;

In FIGURE 1 the arrows indicate the direction of rotation, and the dotted and solid lines indicate the forward and reverse pitch.

At still higher speeds, water resistance increases but the engagement of the tabs 17 in the notches 16 will .retard the rear and intermediate propeller members 13 and-14 to the position of maximum forward pitch provided for in this construction. At this stage, the faces of the propeller blades which have, during construction, been ground and polished in this position, attain maximum eiciency. This finishing of the propeller blades in the forward pitch position will result in reduced eliiciency in reverse pitch position, and coupled with the low rotational speed necessary to attain this position, holds reverse speeds to a safe maximum. n

The operation of the propeller 10 depends on the tension created by the spring 24 and bushing 25 which in normal position retain the members 12, 13, and 14 in reverse pitch position. The engagement of the tabs 17 in the notches 16 retain the members V12, 13, and 14 in cooperative engagement with each other, and the slight clearance of the tabs 17 in the notches 16 provide proper alignment of the members 12, 13, and 14 in the reverse and forward pitch positions. The springs 24 and bushing 25 retarding the change of pitch and the water resistance increasing as the torque ofthe shaft 19 increases to move the members 12, 13, and 14 from normal or reverse pitch to neutral position and iinally to forward position.

Some of the advantages of the present invention are as follows. The propeller is easy to install, and removal of the standard equipment propeller and replacement with -a properly bored and keyed or splined propeller of the present invention will be all that is necessary.A No ma- Y chinery or alteration of the outboard motor is needed, and

the installation of a special control device isl not required or necessary.

Furthermore, response to throttle setting insures sim-y 4 and permit low forward speeds at to attain smooth operation.

The propeller of the present invention is more durable than an outboard propeller built with blades pivoted to a hub (as is the case with aircraft propeller blades). Blades pivoted from a hub could be caused to function in the same manner as the propeller herein described but would prove more susceptible to damage from impact with stumps, stones and other underwater hazards, a factor which has little effect on aircraft propeller design.

The shear pin 23 serves to guard against propeller damage. The resilient or rubber bushing 25 can be used in lieu of the coil spring to prevent corrosion, kand the spiral cut 26 permits the proper amount of flexing. The spinner 21 helps retain the propeller on the shaft.

Minor changes in shape, size and rearrangement of details coming within the field of invention Vclaimed may be resorted to in actual practice, if desired.

I claim: Y

In a torque controlled reversible pitch propeller, a plurality of similar -body members including front and rear body members and intermediate body members, said body members being provided with central circular bores which are arranged in registry with respect to each other, said body members being provided with notches delining olset tabs therebetween, said tabs being arranged contiguous to the bores and receivable in said notches to maintain said body members in proper alignment with each other during the rotation thereof, a cylindrical hub extending through ,said bores and having one Vend secured to the front body member, and resilient means'mounted on said hub and connected to the front and rear body members, the rear body member and intermediate body members being free to rotate on said hub, said resilient means comprising a coil spring, a shear pin extending through the hub and through a shaft positioned in the huh, an end of the shaft being threaded, a cone shaped spinner having suicient engine r.p.m.s

. a threaded socket for receiving -the threadedend of the not operate smoothly at extremelylow speeds and require shaft, `and aset screw extending through the 'spinner and engaging the shaft.

Young 1 Nov. 14, 1911 Hepperle Feb. 2, 1943 

